JP2005054137A - Flame retardant-removing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for producing a non-flame retardant resin by constituting short mixing/kneading machines in multiple stages in order to remove a flame retardant from a flame retardant-containing resin by eluting with a solvent, and treating simply by separating processes of the removal of the flame retardant and removal of the residual solvent. <P>SOLUTION: This flame retardant-removing device is provided by connecting mixing and kneading machines in multiple stages, heating the flame retardant-containing resin in an upper stage machine 1, mixing with the solvent and kneading, then discharging the solvent, moving the resin to the mixing and kneading machine 2 in a later stage, discharging the remaining solvent in the resin with vacuum, ejecting the linear non-flame retardant resin from a mold 9, cutting after cooling and taking it out as a pellet shape. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a flame retardant removing apparatus that removes a flame retardant from a flame retardant-containing resin mainly used in housings of home appliances and the like.

  Conventionally, a lot of synthetic resin is used for a housing or the like in home appliances such as a television. Typical examples include thermoplastic resins such as polystyrene, polypropylene, ABS, and high impact polystyrene (HIPS) with improved impact resistance. Since these generally have low flame retardancy, they are generally flame retardant by adding and containing various flame retardants and flame retardant aids when used as a casing.

  As flame retardants, halogen-based flame retardants, which require a relatively small amount and are inexpensive, are often used. In particular, brominated flame retardants are used in large quantities because they are suitable for polystyrene.

  However, in recent years, an obligation to collect and reuse waste home appliances has been imposed on producers, and a more appropriate processing method than ever has been demanded. In particular, resins such as casings have conventionally been treated by incineration or landfill. However, the halogen-based flame retardants mentioned above, especially brominated flame retardants, are easy to burn incompletely due to their high flame retardancy, and incineration under inadequate conditions such as incineration at low temperatures partially generates dioxins. Concerns have also been raised. Producers are exploring the use of phosphorus-based flame retardants as an alternative, but in phosphorus-based inferior flame retardants, the content is greatly increased in order to obtain the same flame resistance as halogen-based flame retardants. Must be increased to This is not a preferable method from the viewpoint of cost and environmental impact at the time of disposal. Therefore, switching to phosphorus system has not progressed slowly.

  Furthermore, there is an urgent need to save oil resources from the viewpoint of global energy. From that point, recycle recycling of the resin has been addressed conventionally, but for the flame retardant-containing resin, for example, there are acid treatment (Patent Document 1) and high temperature treatment (Patent Document 2). The content is that the resin and the flame retardant are separated and thermally recycled.

That is, no attempt has been made to recycle the material by separating the flame retardant without degrading the properties of the resin and reusing the resin. Patent Document 3 describes a method of modifying and separating a resin from a flame retardant-containing resin.
JP-A-6-157812 JP-A-8-299759 Japanese Patent Laid-Open No. 10-195234

  However, we need mild flame retardant removal technology that suppresses deterioration of the resin as much as possible so that the resin after removing the flame retardant can be used for general-purpose applications similar to the original resin without modifying the resin again. I believe that.

  Therefore, we provide a method for removing a flame retardant from a resin containing a flame retardant with an efficient and low-cost equipment while minimizing a change in the properties of the resin.

  In view of the above-mentioned problems, we put the pulverized flame retardant-containing resin into a combined multi-stage small kneader, heat and melt it, and then inject and discharge a specific solvent from the middle, so that the flame retardant in the solvent This proposes an apparatus for dissolving and extracting slag.

  As described above, by using the method of the present invention, the flame retardant-containing resin emitted from a large amount of waste home appliances with relatively low-cost equipment can be reborn as a non-flame retardant resin without being wasted by incineration or landfill treatment. This has the effect of enabling material recycling and is one of the solutions to environmental problems.

  The present invention is a resin processing apparatus characterized in that a solvent and a resin are kneaded in a kneader configured in multiple stages for extracting and removing the flame retardant from the resin containing the flame retardant, and a plurality of continuous treatment apparatuses It has the function of producing a non-flame retardant resin by removing the flame retardant and the solvent used to extract the flame retardant with a combination of kneaders.

  In the present invention, at least in the first stage kneader, when the solvent and the resin are sufficiently kneaded and the resin is discharged, only a very small amount of solvent penetrating into the resin is contained. It may be a characteristic, and has an action of removing the flame retardant from the resin with this kneader.

  In the final stage kneader, the solvent is completely removed from the resin slightly left in the solvent discharged from the previous stage kneader by using a vacuum pump to remove the solvent. Is characterized in that the flame retardant and the solvent are removed, and has the effect of producing a non-flame retardant resin.

  Further, the present invention is the processing apparatus according to claim 1, wherein the L / D of the multi-stage kneader is at least 7.5 or more and at most 30 or less, and is used with a flame retardant in a short process. It has the effect | action which can remove the used material.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
In the present invention, at least one flame retardant is extracted and separated from the resin by bringing the resin containing the flame retardant into small pieces into contact with the solvent and the solvent in a plurality of kneaders, and further in a subsequent kneader. The residual solvent is removed by evacuation. FIG. 1 is a diagram showing a configuration of a flame retardant removing apparatus according to an embodiment of the present invention.

  The flame retardant-containing resin as used in the present invention refers to unnecessary resins and scraps produced in the resin production process, or those used in waste electrical products collected from the market, regardless of whether it is thermoplastic or thermosetting. Absent. Including at least one flame retardant to add flame retardancy, other flame retardant aids, lubricants, stabilizers, antioxidants, colorants, flow modifiers, release agents, etc. required for resin molding It is a resin containing additives. Moreover, even if the surface is painted, it does not matter as long as the cross section is exposed by crushing.

  Flame retardants include bisphenol A type flame retardants such as tetrabromobisphenol A (TBA), flame retardants such as decabromodiphenyl ether, octabromodiphenyl ether, tetrabromodiphenyl ether, tribromophenol, ethylenebistetrabromophthalimide, hexa Brominated flame retardants such as bromocyclododecane, TBA polycarbonate oligomers, bistribromophenoxyethane, brominated polystyrene, TBA epoxy oligomers, chlorinated flame retardants such as perchlorocyclopentadecane, chlorendic acid, chlorinated paraffin, phosphorus-based flame retardants And nitrogen compound flame retardant inorganic flame retardant.

  The flame retardant in the resin may be used alone or in combination with a plurality of the various flame retardants described above. The content varies depending on the required flame retardant grade, but is generally from several wt% to 50 · 60 wt%.

  The type of resin is not particularly selected, but is particularly effective for styrene resins. Examples of styrene-based materials include polystyrene, high impact polystyrene, styrene-budadiene-acrylonitrile, styrene-butadiene, poly-α-methylstyrene, styrene-acrylonitrile, and styrene-maleic anhydride.

  The above resins may be used alone, but may be used by blending with other resins. The molecular weight is not particularly limited, but is preferably about 3,000 to 1,000,000.

  The kneading machine in the present invention is a multi-stage structure connected in series, regardless of whether it is a single shaft or two shafts, and refers to a kneader used for resin molding or resin kneading. There is a portion where the solvent is injected / discharged at the intermediate portion, and the structure can be evacuated near the resin discharge portion, including those appropriately improved.

  The solvent used in the present invention can separate the flame retardant dissolved by the distillation operation, and the solvent can be recycled.

  Hereinafter, the operation of the present invention will be described in detail with reference to FIG.

  The flame retardant-containing resin that has been used in the collected waste home appliance housing or the like is pulverized into pellets having a size of 1 to 10 mm, and then charged into the hopper 4. When this is introduced into the first stage kneader 1, it is heated and melted in the kneader, further kneaded by the screw 15, and sequentially pushed out toward the outlet on the right side. This extruder may be of a normal L / D length for resin molding, but if the screw configuration is devised, a kneader dedicated to kneading with an L / D of about 10 or less, which is less than a fraction of the price. Can also be used. As a result, the price of the apparatus is greatly reduced, and it is possible to produce at low cost.

  From the tube 6 provided in front of the resin discharge portion of the first stage kneader, the solvent is injected while applying pressure and discharged from the tube 5. During this time, the solvent and the resin come into contact with each other at a high temperature, and the flame retardant is eluted in the solvent. The flow of solvent and resin is opposite, and the resin is always in contact with new solvent near the outlet, so it is finally washed with the cleanest solvent.

  Although the heating temperature of this kneader varies depending on the resin, it is in the range of about 100 to 200 ° C., and in the case of high impact polystyrene, it is about 180 ° C. As a result of studying various solvents, a glycol ether type solvent was selected as one in which the flame retardant dissolves relatively easily, the resin component hardly dissolves, and has little influence on the environment. Specifically, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol propyl ether, diethylene glycol butyl ether, triethylene glycol methyl ether, triethylene glycol ethyl ether, triethylene glycol propyl ether, Examples include triethylene glycol butyl ether, tripropylene glycol methyl ether, tripropylene glycol ethyl ether, tripropylene glycol propyl ether, and tripropylene glycol butyl ether.

  Moreover, if it is a range which does not drop the dissolving power of a flame retardant in these solvents, a well-known additive can be added as needed. For example, antibacterial agents, antifungal agents, antioxidants, pest repellents, surfactants, coloring agents, foaming agents, flow promoters and the like.

  Thereafter, the discharged resin enters the kneading machine 2 through the pipe 7 that is a joint portion with the kneading machine 2 in the subsequent stage. In this kneader, the solvent remaining in the resin is removed by suction from the vacuum exhaust port 13 and is discharged linearly through the mold 9. Since the purpose of this kneading machine is to remove the solvent, it is not necessary to have the same L / D as that of the kneading machine 1, and if it can be reduced to the desired solvent content, a smaller and lower price kneading machine can be obtained. It is also possible to use it.

  The resin 10 thus extruded is then cooled in a water tank, cut to a predetermined length by a pelletizer 12, and can be regenerated as non-flame retardant resin pellets 16 again.

(Embodiment 2)
In this embodiment, a crushed case resin of a waste TV is used as a raw material. The type of resin is high impact polystyrene, and the flame retardant contained is TBA (tetrabromobisphenol A). The average molecular weight was about 40,000. According to GPC analysis, the flame retardant content was about 17%.

  This was put into a hopper and put into a first-stage kneader. The temperature setting of the kneader is 180 ° C. Dipropylene glycolol was used as the solvent. The pressure was increased using a gear pump in the kneader in a direction opposite to the resin flow direction. When the discharged solvent was analyzed, it contained about 7% TBA. Next, the resin moves through the connection pipe to the second stage kneader. It is heated again in this kneader and evacuated from the vent port, whereby the solvent remaining in the resin is extracted. Note that the solvent contained in the exhaust gas can be reused by returning to a liquid state by cooling in the exhaust process.

  The resin is discharged in a plurality of lines from a mold attached to the outlet of the second-stage kneader, cooled by being immersed in a cooling tank, and cut into a pellet size by a pelletizer. When this resin was analyzed, the residual solvent ratio was 0.1% or less, and the residual flame retardant ratio was 0.05% or less. Moreover, when various physical properties of this resin were measured, the physical properties such as Charpy impact strength, DuPont impact value, Vicat softening point were all about 1.2 times that of the initial high impact polystyrene. This is because the physical properties that have been lost by adding the flame retardant to the resin have returned to the original level of the resin by removing the cause of the flame retardant. The molecular weight of the resin was 38500, and there was almost no change from the initial value.

  That is, the flame retardant could be removed from the resin with almost no deterioration of the resin properties.

  By using the present invention, there is an effect that a flame retardant-containing resin from a waste home appliance is reborn again as a non-flame retardant resin and can be recycled, and the present invention is used in other industrial products. It can also be used to recycle resins, for example, products such as furniture, automobiles, buildings, etc., and is one of the solutions to environmental problems.

Schematic diagram of the device of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st stage kneader 2 2nd stage kneader 3 Hopper 4 Crushed resin 5 Solvent discharge port 6 Solvent supply port 7 Connection part 8 Motor 9 Mold 10 Discharge resin 11 Cooling water tank 12 Pelletizer 13 Exhaust 14 Vent port 15 Screw 16 pellet

Claims (3)

A flame retardant removing apparatus, wherein a solvent and a resin are kneaded in a kneader comprising a plurality of stages when the flame retardant is extracted from a resin containing the flame retardant. The flame retardant removing apparatus according to claim 1, wherein the final stage kneader is provided with a vacuum pump, and the vacuum pump exhausts the solvent from the resin discharged from the previous stage kneader. The flame retardant removing apparatus according to claim 1, wherein L / D of the multistage kneader is at least 7.5 or more and at most 30 or less.

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